Zone 6 planting calendar
Typical frost dates for USDA hardiness zone 6, and a month-by-month table of when to start seeds and plant out. Your own dates depend on your location within the zone, so use these as a starting point.
Zone 6 at a glance
From NOAA 1991–2020 climate normals for 13 example stations in zone 6 (32°F threshold, 50% probability).
Zone 6 is about winter cold, not spring frost
The USDA Plant Hardiness Zone Map divides the country by the average coldest winter night: each zone covers 10°F, and the "a" and "b" halves cover 5°F each. Zone 6 is the right guide for choosing perennials that survive the winter. It is only a rough guide to planting dates, because places with similar winter lows can have very different springs. That is why this page gives a range of frost dates rather than a single date, and why the frost date for your own location is a better input for the seed starting calculator.
Zone 6 has a season long enough for most vegetables, including melons and winter squash with a little planning. The example stations run from Kansas City and Indianapolis in mid-April to Denver in early May, and Denver's later date is a good reminder that elevation matters as much as latitude. A spring crop of brassicas and a fall crop sown in late summer are both realistic here.
Typical frost dates in zone 6
The table lists example cities whose airport or city weather station falls in zone 6. "Last frost" is the date after which a 32°F freeze has a 50% chance of still happening; the "1-in-10" column is the date after which there is only a 10% chance. Planting tender crops after the 1-in-10 date is the cautious choice.
| City (station) | Zone | Last frost (median) | Last frost (1-in-10 later) | First fall frost (median) | Freeze-free days |
|---|---|---|---|---|---|
| Kansas City, MO | 6b | Apr 13 | Apr 29 | Oct 24 | 193 |
| Indianapolis, IN | 6b | Apr 15 | May 2 | Oct 26 | 193 |
| Chicago (O'Hare), IL | 6a | Apr 16 | May 1 | Oct 28 | 193 |
| Omaha, NE | 6a | Apr 18 | Apr 30 | Oct 21 | 185 |
| Hartford, CT | 6b | Apr 21 | May 6 | Oct 16 | 177 |
| Columbus, OH | 6b | Apr 22 | May 9 | Oct 23 | 183 |
| Pittsburgh, PA | 6b | Apr 23 | May 12 | Oct 23 | 181 |
| Lincoln, NE | 6a | Apr 24 | May 7 | Oct 13 | 171 |
| Spokane, WA | 6b | Apr 26 | May 10 | Oct 12 | 168 |
| Albany, NY | 6a | Apr 27 | May 11 | Oct 15 | 169 |
| Grand Rapids, MI | 6a | Apr 29 | May 15 | Oct 20 | 174 |
| Lansing, MI | 6a | May 1 | May 18 | Oct 13 | 162 |
| Denver, CO | 6a | May 5 | May 19 | Oct 9 | 156 |
Zone shown is the 2023 USDA zone for the ZIP code nearest each weather station, via PRISM data. Frost dates are NOAA 1991–2020 normals for that station. Dates for nearby gardens can differ by a week or more with elevation, slope and distance from water. Find your own station on NOAA's map (see how to find your frost dates).
Month by month: what to start when in zone 6
This table uses the middle example above, Pittsburgh, PA (median last frost Apr 23), and the University of New Hampshire Extension seed-starting timings. If your last frost is a week later, move everything a week later.
| Month | Start seeds indoors | Plant transplants out | Direct sowing reminders |
|---|---|---|---|
| January | Onions (Jan 15–Jan 29) Parsley (Jan 22–Jan 29) Spinach (Jan 29–Feb 12) | — | — |
| February | Broccoli (Feb 12–Feb 26) Cabbage (Feb 12–Feb 26) Kale (Feb 12–Feb 26) Lettuce (Feb 19–Feb 26) Peppers (Feb 26–Mar 12) Eggplant (Feb 26–Mar 12) Cauliflower (Feb 26–Mar 12) | — | — |
| March | Tomatoes (Mar 5–Mar 19) Basil (Mar 12–Mar 26) | Spinach (Mar 12–Apr 2) Broccoli (Mar 26–Apr 9) Cabbage (Mar 26) Lettuce (Mar 26–Apr 2) Kale (Mar 26) Onions (Mar 26) | Spinach, lettuce, kale: direct sow once the soil can be worked (see guides) |
| April | Cucumbers (Apr 2–Apr 9) Squash & zucchini (Apr 9–Apr 16) Melons (Apr 9–Apr 16) | Parsley (Apr 2–Apr 9) Cauliflower (Apr 9) Tomatoes (Apr 30–May 7) Cucumbers (Apr 30–May 7) | Cucumbers, squash: direct sow once soil reaches 70°F, usually after this date |
| May | — | Peppers (May 7) Eggplant (May 7–May 14) Squash & zucchini (May 7) Melons (May 7) Basil (May 7) | Melons: direct sow or transplant once soil is at least 65°F |
Open this schedule in the calculator
Direct-sowing reminders follow the soil-temperature rules in each crop guide (for example, 70°F soil for cucumbers and squash), so the real date depends on your weather. For fall crops, count back from your first fall frost with the fall planting calculator.
Crop guides
Frequently asked questions
When is the last frost in zone 6?
It depends on where you are in the zone. Among the 13 example weather stations on this page, the median last spring freeze (32°F, 1991–2020 NOAA normals) ranges from Apr 13 to May 5. Look up the station nearest you for a better estimate.
When should I start tomato seeds in zone 6?
For the middle example on this page (last frost Apr 23, Pittsburgh, PA), the University of New Hampshire Extension timing gives an indoor sowing window of Mar 5–Mar 19 and setting out Apr 30–May 7. Shift those dates by the difference between your own last frost date and Apr 23.
Is my hardiness zone the same as my frost date?
No. USDA hardiness zones are based on the average annual extreme minimum winter temperature. They tell you which perennials survive winter, not when spring frosts end, which is why frost dates vary so much within one zone.
Sources
- USDA ARS — Plant Hardiness Zone Map
- PRISM Climate Group, Oregon State University — USDA Plant Hardiness Zone Map data (2023); ZIP lookups via phzmapi.org (not the official USDA map)
- NOAA NCEI — U.S. Climate Normals (1991–2020), incl. interactive map with frost/freeze dates
- University of New Hampshire Extension — Growing Vegetables: When to Plant Your Vegetable Garden
Station data retrieved from NOAA NCEI on 22 Oct 2026. Last reviewed 2026-10-23. Found an error? Tell us.